InterviewSolution
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Directions: In the following question, two statements are numbered as Quantity I and Quantity II. On solving these statements, we get quantities I and II respectively. Solve both quantities and choose the correct option.Quantity I: Find the total surface area of a hemisphere where the total surface area of the sphere is 3 times the curved surface area of a cone whose radius and height are 6 cm and 8 cm respectively. (take π = 3.14)Quantity II: Find the total surface area of the cuboid whose length, height, and breadth are in the ratio 5 ∶ 2 ∶ 3. Given the difference between the length and bredth is 5 cm. 1. Quantity I > Quantity II2. Quantity I < Quantity II3. Quantity I ≤ Quantity II4. Quantity I ≥ Quantity II5. Quantity I = Quantity II or relation cannot be established. |
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Answer» Correct Answer - Option 1 : Quantity I > Quantity II Given: Quantity I: Radius and height of the cone = 6 cm and 8 cm The total surface area of sphere = 3 × curved surface area of the cone Quantity II: The ratio of length, height, and breadth of cuboid = 5 ∶ 2 ∶ 3 Difference between length and height = 5 cm Concept used: The volume of sphere = 4/3 × π × r3 The total surface area of sphere = 4πr2 The curved surface area of cone = π × r × l Where l = √(r2 + h2) Total surface area of the cuboid = 2 × (lb + bh + hl) Where, l, b, and h are the length, breadth, and height. Calculation: Quantity I: l = √(62 + 82) = 10 cm curved surface area of cone = π × 6 × 10 = 60π total surface area of sphere = 4πr2 = 3 × 60π ⇒ r2 = 45 cm2 Total surface area of the hemisphere = 3πr2 = 3π × 45 Total surface area of the hemisphere = 135 × 3.14 Quantity I = 135 × 3.14 = 423.9 cm2 Quantity II: Ratio of length, height and breadth of cuboid = 5 ∶ 2 ∶ 3 Then, length, breadth and height of cuboid will be = 5x, 3x and 2x Difference between length and breadth = 5x – 3x = 2x ⇒ 2x = 5 Or, x = 5/2 cm Total surface area of the cuboid = 2 × (15x2 + 6x2 + 10x2) = 62 × (5/2)2 Quantity II = 62 × (5/2)2 = 387.5 cm2
∴ From the table, we can see that Quantity I > Quantity II. |
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